Co‐Induced Electronic Optimization of Hierarchical NiFe LDH for Oxygen Evolution

Developing efficient and stable non‐noble electrocatalysts for the oxygen evolution reaction (OER) remains challenging for practical applications. While nickel–iron layered double hydroxides (NiFe‐LDH) are emerging as prominent candidates with promising OER activity, their catalytic performance is still restricted by the limited active sites, poor conductivity and durability. Herein, hierarchical nickel–iron–cobalt LDH nanosheets/carbon fibers (NiFeCo‐LDH/CF) are synthesized through solvent‐thermal treatment of ZIF‐67/CF. Extended X‐ray adsorption fine structure analyses reveal that the Co substitution can stabilize the Fe local coordination environment and facilitate the π‐symmetry bonding orbital in NiFeCo‐LDH/CF, thus modifying the electronic structures. Coupling with the structural advantages, including the largely exposed active surface sites and facilitated charge transfer pathway ensured by CF, the resultant NiFeCo‐LDH/CF exhibits excellent OER activity with an overpotential of 249 mV at 10 mA cm−1 as well as robust stability over 20 h. Hierarchical nanostructures fabricated from edge‐rich nickel–iron–cobalt layered double hydroxides (NiFeCo‐LDH) nanosheets and carbon fiber are synthesized by solvent‐thermal treatment of ZIF‐67/CF. Owing to the synergistic interaction between the three metal ions, largely exposed active surface sites and tunable electronic structure in LDH materials, NiFeCo‐LDH/CF displays superior oxygen evolution reaction performance and robust stability.